In a multiple processor system which executes a symmetric multiple processor (SMP) OS (SMP OS) on the SMP, for example, as a multiple processor system which causes an OS for a multiple processor to operate on a multiple processor, a plurality of CPUs are designed to equivalently take charge of processing of an application, so that changing a structure of an execution environment formed of a combination between processing to be executed according a state of a load of a CPU under the SMP OS and a CPU realizes efficient processing.
There exists, as such a multiple processor system, a system disclosed in related Literate 1 (Japanese Patent Laying-Open No. 2002-278778).
In the multiple processor system disclosed in the related Literature 1, with respect to all the processes (processing) executed within a certain fixed time period, determine whether a process should be executed by one specific CPU or not and when the ratio of the number of processes which is determined to be executed by one specific CPU to the total number of processes exceeds a threshold value, determine that with respect to all the processes, the specific one CPU should execute all the threads, thereby eliminating management of order in thread execution, synchronization between a cache memory and a main storage contained in each CPU, and exclusive utilization management processing for the main storage and input/output which are causing overhead.
Patent Literature 1: Japanese Patent Laying Open No. 2002-278778.
The above-described related art multiple processor system has the problems set forth below.
First, the system recited in the related Literature 1 or the like is designed to have a plurality of CPUs equivalently take charge of a plurality of processings of an application and only to change a structure of execution environments (a combination between a CPU and processing) with a CPU load state as a condition, so that it is impossible to set up an execution environment whose stability or security level is changed with each processing.
When executing fundamental processing (basic processing) of an application and incidental processing (additional processing) which is to be executed in line with the basic processing and arbitrarily added or deleted, for example, it is impossible to set up an execution environment for executing the basic processing and an execution environment for executing the additional processing while taking stability or a security level into consideration (with stability and a security level of a basic processing execution environment increased).
More specifically, in a case of simultaneously executing a plurality of processings whose required stability differs from each other, the problem occurs that such environment set-up is impossible as for executing processing which requires high stability and the other processing under different execution environments.
Other systems than a multiple processor mounted with SMP OS also have the same problem as that described above.
An object of the present invention, aiming at solving the above-described problems, is to provide a multiple processor system, a system structuring method in a multiple processor system and a program thereof which enable an execution environment to be flexibly set up according to contents of processing to be executed while taking stability and a security level into consideration.
Another object of the present invention is to provide a multiple processor system, a system structuring method in a multiple processor system and a program thereof which enable execution environment switching (structure change) to be realized at a high speed according to each processing content.